This application claims priority to Canadian Application No. 2,329,408 filed Dec. 21, 2000.
The present invention relates to heat exchangers, and in particular, to heat exchangers useful as fuel coolers for automotive engines.
In recent years, it has become desirable, if not necessary, to cool the fuel used by the engines of motor vehicles especially diesel engine powered vehicles. The most convenient way to do this is to insert a heat exchanger in series in a fuel line running between the engine and the fuel tank of the motor vehicle. Further, in order to keep the installation of these heat exchangers as simple and inexpensive as possible, air cooled heat exchangers are sometimes chosen in order to eliminate the need for coolant lines to be run to the heat exchanger.
Since the fuel lines usually run along the underside or underbody of the motor vehicle, it has been found to be convenient to mount the fuel coolers on the underbody of the vehicle. A difficulty with this, however, is that the heat exchangers are exposed to the elements and thus subject to damage. In northern climates, ice and snow can also cause a problem with the efficiency of the heat exchangers. Another concern is that the heat exchangers must be low in height or have a low profile in order to provide sufficient clearance between the underbody of the vehicle and the road surface.
One attempt to meet the desired design criteria and overcome the above-mentioned difficulties is shown in European patent application No. EP 0 890 810 published on Jan. 13, 1999. This patent shows a fuel cooler that has an extruded or continuously cast main body containing a plurality of longitudinal internal flow channels. This main body has open ends. Another member with cooling ribs or fins is attached to the main body. Finally, end pieces or closing elements are used to close off the open ends of the main body and make the fuel flow in series through the fluid channels in the main body. This heat exchanger is difficult and expensive to manufacture, however, because of the number and complexity of the individual components and the need for a special tooling to make these components.
In the present invention, heat exchangers are provided that are much simpler and easier to manufacture, and which require much less expensive tooling to make the required components.
According to one aspect of the invention, there is provided a heat exchanger comprising an elongate base member including a planar central portion having first and second side surfaces and a plurality of spaced-apart fins extending from one of the first and second side surfaces. A cross-over member is connected to the other of the first and second side surfaces and defines spaced-apart flow channels for the flow of a heat exchange fluid over the planar central portion. The flow channels have opposed inlet and outlet end portions. One of the cross-over member and the base member is formed with spaced-part, inlet and outlet manifolds communicating respectively with the inlet and outlet end portions. Also, inlet and outlet fittings communicate respectively with the inlet and outlet manifolds.
According to another aspect of the invention, there is provided a method of forming a heat exchanger comprising the steps of extruding a base member having a planar central portion and spaced-apart fins extending from one side of the planar central portion. A cross-over member is formed having a plurality of spaced-apart transverse flow channels therein. A pair of spaced-apart flow manifolds is formed in one of the base member and the cross-over member. Also, the cross-over member is attached to the planar central portion, so that the flow manifolds and flow channels communicate with each other and the planar central portion.
According to yet another aspect of the invention, there is provided a method of forming a heat exchanger comprising the steps of extruding a base member having a planar central portion and spaced-apart fins extending from one side of the planar central portion. The base member also has a pair of spaced-apart inlet and outlet manifolds extending transversely from the planar central portion in the same direction as the fins. A cross-over member is formed having a plurality of spaced-apart flow channels formed therein. The flow channels have opposed inlet and outlet end portions. Also, the cross-over member is attached to the planar central portion, so that the opposed inlet and outlet end portions communicate with the respective inlet and outlet flow manifolds.